How not to have a blast

Japan’s authorities issue volcano safety guidelines for hikers

One-third of Japan’s popular One Hundred Mountains are active volcanoes. This can lead to tragedy. In September 2014, a sudden eruption on a volcano in central Honshū killed 63 people. Some of the victims were never found. To raise awareness of these hazards, Japan’s Home Ministry and its Meteorological Agency have recently issued a leaflet for hikers.

How volcanoes can damage your health

What follows is an outline summary of the Japanese text (PDF). The front sheet of “Be prepared for hiking on volcanoes” (火山への登山のそなえ) marks the location of Japan’s 110 active volcanoes – “active” means showing signs of life, or having erupted within the last 10,000 years. The 33 active volcanoes selected by Fukada Kyūya for his One Hundred Mountains are distinguished in red.

Red captions mark the active Nihon Hyakumeizan

Next are points to keep in mind when climbing a volcano:

• Eruptions can occur without warning, so stay alert to what is happening in and around the crater.
• If you see any unusual venting of steam or gases, take refuge or descend immediately and warn the local authorities, police or Meteorological Agency (which is responsible for monitoring volcanic activity in Japan).
• As volcanic gases are heavier than air, they tend to collect in hollows and valleys. Stay out of such locations.
• Keep your mobile phone on and check for official hazard alerts. Be aware of whether your phone has a connection to the network. Information about mobile phone coverage is published on the websites of some phone companies, or marked on certain hiking maps. Try to establish whether and where you will have mobile phone connectivity before you leave home.
• During an eruption, there is a major risk of death or injury from flying stones and lava bombs near the crater. Get away from the crater and take shelter in a hut or behind a rock. If you have them, put on a helmet and goggles, and breathe through a face-mask or towel.

Things not to leave home without

In addition to your normal hiking kit, map and compass, you should consider carrying a copy of the local volcanic hazard map, which will show you the range of previous eruptions, and also places to take shelter. A helmet, goggles and a towel will protect against ash and other fall-out, as will a rain-jacket. A headlight will help in bad visibility. And don’t forget a spare battery for your mobile phone and emergency rations/water for yourself.

The last sheet of the leaflet starts with a reminder of the 2014 Ontake disaster. Then (see top graphic) two cartoon volcanoes present the various types of eruptive threat – showers of heavy rocks that can fly up to four kilometres from the vent; smaller stones with a lethal range of 10 kilometres; volcanic ash that may, in the leaflet’s measured language, “affect your breathing”, pyroclastic flows that burn and bury; volcanic gases and mudflows. Each category is illustrated from an eruption in living memory.

The message is clear: these hazards are for real.

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